1. Field of the Invention
The invention generally relates to a cooling fin structure, and more particularly to a structure of cooling fins arranged in a zigzag form.
2. Description of the Related Art
A cooling fin device that arms at improving the cooling efficiency of cooling fins of a heat sink provided in an electronic device is disclosed in Japanese Patent Application Publication No. 2002-185175 (JP 2002-185175 A). In the cooling fin device disclosed in this publication, the cooling fins are discretely placed like pin-type fins, and have a streamline shape relative to the direction of flow of cooling water.
Also, a cooling device for a semiconductor device as disclosed in Japanese Patent Application Publication No. 2003-324173 (JP 2003-324173 A) arms at efficiently dissipating heat while reducing a pressure loss in a coolant channel. In the cooling device for the semiconductor device as disclosed in this publication, protruding elements shaped like fins are formed such that the length or height of the protruding elements is maximized in a region corresponding to substantially the center of the semiconductor device, and the length of the protruding elements gradually decreases toward the outer side. Each of the protruding elements has a spindle shape in a transverse cross-section.
As disclosed in the above-identified publications, coolers in which pin fins are placed on a coolant passage are used for cooling various types of electronic devices that generate heat. As typical arrangements of the pin fins, the pin fins may be arranged in the form of a matrix, or the pin fins may be arranged in a zigzag form.
Where the pin fins are arranged in a zigzag form, the coolant passes through clearances between pin fins arranged in a row, and is then confronted with another row of pin fins present ahead of the coolant. Therefore, the coolant proceeds while winding toward the opposite sides relative to the direction of flow of the coolant. In this case, the pressure loss in the flow of the coolant that flows in the coolant passage is increased, as compared with the arrangement of pin fins in a matrix form through which the coolant proceeds almost straight. The increase in the pressure loss in the flow of the coolant may result in increase of a load on a motor for supplying the coolant, and reduction of the cooling efficiency with which the electronic device is cooled. In order to improve the cooling efficiency of the electronic device, it is necessary to efficiently transfer heat from the pin fins to the coolant, as well as reducing the pressure loss in the flow of the coolant.